Fluid translating apparatus



Aug. 31, 1943- J. G. RITTER 2,328,296

FLUID TRANSLATING APPARATUS Filed Aug. 3, 1940 Z-Sheets-Sheet 1 WITNESSES: J INVENTQR 7 I f pa, QHN G- 775 2 ATTORNEY Aug. 31, 1943. J. G. RITTER 2,328,296

FLUID TRANSLATING APPARATUS Filed Aug. 5,1940 2 Sheets-Sheet 2 Ira-.3- 36 mum! ' WITNESSES: 7 J GINVENTOR 7? I CH N I 7' TE? BYW ATTORNE Patented Aug, 31, 1943 7 12,328,296 l FLUIVII-TRANQSLATING nerm'rus t John G. Ritter, Springfield, Masa, assig'nor' w Westinghouse Electric & Manufacturing Company,.. East Pittsbur 1 Pennsylvania 8 a; corpcratiomof Application August 3, 1940, Serial N 350,207 s oiaims. (01. 184-6 Myfihvention'relates to fluid translating apparatus, more particularly' to a motor compressor unit of the enclosed type used in a refrigerating system, and it has'for an object to provide impxo'vedhpparatus. e A particular object. is ,to prevent or control lengthwise. oscillation offthe rotating shaft in? motor compressor units'l of the enclosed type.

In anumbe'r'of' motorTco'mpressor units' sed in refrigerating apparatus, difficulty was en,- countered due to ,failure of fthe oilpump. These units were provided.withfloilpumps driven by therotating shaft through helical gears. The teeth of these gears had been worn about, onehalf way through andi had broken off. In investigating one of these failures, .1 found that there was considerable end clearance oftheshaft, and I concluded that the difficulty was probably due to lengthwise oscillation of the shaft. which might becaused by several conditions, under which the unit was operating, Due to the. angle of the, gear teeth, such oscillationswould accelerate and decelerate the oil pump.

In similar units. previously constructed, such oil pump failures hadnotoccurred to any appreciable extent, Those unitswere not of the enclosed type but had shaft seals which biased the shaft lengthwise and which a arently held the.

shaft against its thrust bearing andthereby minimized or controlled the lengthwise movement of the shaft In the preferred embodiment of my invention, the end bearing of the compressor remote from the motor is formed with a chamber, and I introduce oil under suitable pressure into this chamber to bias theend of the shaft against the thrust hearing at the motor end. In motor compressor unitsembodying this invention, no

- oil pump failures have occurred.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawings, forming a part of this application, in which:

Fig. 1 is a side elevation, with parts in section, of a motor-compressor unit incorporating my invention;

Fig. 2 is an enlarged detail sectional view; and I Fig. 3 is a sectional perspective view of the bearing shell and lining, the section being taken on the line IIIIII1 bf Fig. 2,

Referring to the drawings in detail, I show a motor-compressor unit which includes a recip- ,rocating compressor l and a motor II directly connected to the compressor for driving the same.

i The compressor and the motor are enclosed in a common fluid-tightcasing' l2, so thatlit is, not necessaryto provide a shaft sealbetween the compressor and themotor. I

The compressor H1 may be of any construction suitable for a reciprocating compressor'andlincludes a crankshaft l3; The compressor'is' provided with an 'end bearing I4, an intermediate bearingl5 andamotor endbeari'ng l6. Eachof these bearingsincludes aljournal bearing portion and the end bearings l4 and Hi. also include thrust bearingportions which may bereferredto. as the thrust bearings l1 and lfl'frespecti'vely. The crank shaft is formed witha thrustshoulder N which engages the thrust bearing M1,. The bearing Mincludes a, cap member. 2!; which forms a closurefor the crank case, a bearing shell 22 and a bearing lining .2'3.;

The lubrication system for the unit includes-an oil pump 24. drivenbylthe cranl; shaft Ht-through gears 25 audit The gears 25 and26 areformed. with suitable meshing helical gear teeth. Oil

is .supplied from the pump 24 to the bearings through suitable passages. including a verticalpassage 21 and an annular passage 28 formed the bearings I5 and Hi to provide oil thereto.

In order to control the pressure of the oil supplied to the bearings, suitable pressure relief valves 34 are provided and are set to maintain a pressure of #/sq. in.

In accordance with my invention, I utilize the oil pressure developed by the'pum'p 24 for applying pressure endwise on the crankshaft l3 to hold it against the thrust bearing l6, thereby to prevent lengthwise oscillations of the crankshaft. The bearing member 2| is formed with a thrust bearing I 8 but at the same time, it should not be so great as to cause undue friction with said thrust bearing. Accordingly, the pressure in the chamber 35.

the chamber 35 will ordinarily be lower than the pressure of the oil supplied to the bearings. For example, I ordinarily prefer to maintain a pressure of about 11 pounds per square inch in the chamber 35, and the pressure-relief valve 31 is designed or adjusted to maintain such pressure.

In the operation of the motor-compressor unit, the pump 24 draws oil from the body of oil provided in the bottom of the crankcase, and discharges the same under pressure. The several passages convey the oil to the bearings and the pressure-relief valves maintain the pressure of the oil in these passages substantially constant.

The orifice 3B permits a restricted flow of oil supplied to the bearing M from the groove 3| to The pressure-relief valv 3'! maintains the pressure in the chamber 35 at substantially 11 pounds per square inch by controlling the discharge of oil to the crankcase. The fluid pressure in the chamber 35 biases the crankshaft toward the mot-or end, thereby maintaining the thrust shoulder IS in contact with the thrust bearing [8. The crankshaft is thereby maintained in a fixed axial position and lengthwise oscillations thereof are prevented or at least controlled so as to be unobjectio-nable.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. The combination with a machine having a horizontal rotating shaft, bearingsther-efor including journal bearings and a thrust bearin forming a positive stop that limits endwise movement of the shaft and thereby positions the shaft, an oil pump and gears having helical teeth for driving the oil pump from said shaft, of means for'imposing a substantiallyconstant fluid pressure on said shaft biasing the same lengthwise against said thrust bearing, the axial forces, other than said fluid pressure, biasing said shaft against said thrust bearing being insufilcient to prevent axial oscillation of the shaft.

2. The combination with a machine having a horizontal rotating shaft, bearings therefor including journal bearings and a thrust bearin supplying oil under pressure to said chamber, and

means maintaining the pressure of the oil in said chamber substantially constant, the axial forces on said shaft, other than said fluid pressure, be-

ing insufiicient to prevent axial oscillation of v the shaft.

3. The combination with a machine having a horizontal rotating shaft, bearings therefor including journal bearings and. a thrust bearing, an oil pump for lubrication of said bearings, and gears having helical teeth for driving said oil pump from said shaft, of means for preventing lengthwise oscillation of the shaft comprising means providing a chamber arranged so that the fluid pressure therein biases the shaft axially against said thrust bearing, means for conveying oil under pressure from said pump to said bearings, a pressure relief valve for exhausting oil from said conveying means to maintain said pressure substantially constant, means including an orifice for providing a restricted flow of oil from the conveying means to said chamber, a second pressure relief valve for exhausting oil from said chamber and maintaining the pressure therein at substantially constant value lower than the pressure in said conveying means.

4. The combination with a motor-compressor unit having a casing forming a fluid-tight enclosure for the compressor and the motor and including a horizontal rotating shaft, bearings therefor including a thrust bearing forming a positive stop that limits endwise movement of the shaft and thereby positions th shaft, an oil pump, and gears havinghelical gear teeth for driving the oil pump from said shaft, of means for preventing lengthwise oscillation of the shaft comprising means for imposing fluid pressure on said shaft biasing the same lengthwise against said thrust bearing, the axial forces on said shaft, other than said fluid pressure, being insufficient to prevent lengthwise oscillation of the shaft.

JOHN G. BITTER. 

